Electron energy analyzers are essential components of a number of electron devices, most particularly analytical instruments which determine the composition and properties of materials based upon the energy distribution of electrons their surfaces emit when stimulated appropriately. Two widely used instruments which utilize electron energy analyzers are x-ray photoelectron spectrometers (XPS), and auger electron spectrometers (AES). In these systems, the resolution (ability to distinguish different elements and chemical bonds in the material being analyzed) and sensitivity (the minimum detectable level of these constituents) of the instruments are largely determined by the electron energy analyzer. To be useful in these applications, an electron energy analyzer must be able to distinguish electrons of energies on the order of 1000 electron volts which differ in energy by less than 1 electron volt.
Two types of electron energy analyzers are in wide usage today: the Cylindrical Mirror Analyzer (CMA) and the Spherical Capacitor Analyzer (SCA), both electrostatic analyzers. Both are described extensively in the literature. There are also a wide variety of other types of electron energy analyzers which have been described, see, for example, J. C., Riviere, Surface Analytical Techniques, Clarendon Press (1990), p. 52.
The analyzers discussed above have limited sensitivity: all are capable of selecting only a single energy or a small range of energies to be routed to a detector. Typically, both the CMA and the SCA are able to accommodate only a fraction of a percent of the electrons emanating from a sample under analysis, and must be sequentially scanned over a broad range of energies in order to develop a complete spectrum which identifies the material being analyzed. As a result, the material must be illuminated by an intense beam of electrons or x-rays in order to perform the analysis. This causes undesirable sample damage, and slows the analysis considerably.
A long felt need exists for an electron energy analyzer with increased resolution and sensitivity for simultaneously detecting and analyzing all energies of all particles in a beam having a multitude of energies.